Evaluating the potential of microplastics ingestion to harm the sea cucumber Holothuria sanctori : Results and implications of a feeding experiment conducted on Madeira Island

The omnipresence of microplastic particles (< 5 mm) in the marine environment has raised concerns about their potential to harm organisms both physically and chemically, for example via the transfer of pollutants adsorbed from seawater. While many species are able to ingest microplastics, little is known about the consequences. Moreover, previous studies have mostly applied exaggerated scenarios of microplastics concentrations or associated pollution levels. The present study investigated the potential effects of microplastics ingestion under more realistic conditions. We exposed the sea cucumber Holothuria sanctori – a prevalent deposit feeder of the rocky shores around Madeira Island – to an environmentally relevant concentration of microplastic particles in the feeding sediment for 2 months. The polystyrene beads used as model microplastics were previously exposed in situ to seawater with different levels of pollution (low and high). (…)